<template>
    <collapse-transition>
        <ul :class="classes">
            <li>
                <span :class="arrowClasses" @click="handleExpand">
                    <Icon v-if="showArrow" type="arrow-right-b"></Icon>
                    <Icon v-if="showLoading" type="load-c" class="ivu-load-loop"></Icon>
                </span>
                <Checkbox
                        v-if="showCheckbox"
                        :value="data.checked"
                        :indeterminate="data.indeterminate"
                        :disabled="data.disabled || data.disableCheckbox"
                        @click.native.prevent="handleCheck"></Checkbox>
                <Render v-if="data.render" :render="data.render" :data="data" :node="node"></Render>
                <Render v-else-if="isParentRender" :render="parentRender" :data="data" :node="node"></Render>
                <span v-else :class="titleClasses" @click="handleSelect">{{ data.title }}</span>
                <Tree-node
                        v-if="data.expand"
                        v-for="(item, i) in children"
                        :key="i"
                        :data="item"
                        :multiple="multiple"
                        :show-checkbox="showCheckbox"
                        :children-key="childrenKey">
                </Tree-node>
            </li>
        </ul>
    </collapse-transition>
</template>
<script>
// import Checkbox from 'node_modules/iview/src/components/checkbox/checkbox.vue';
// import Icon from 'node_modules/iview/src/components/icon/icon.vue';
import Render from './render'
import CollapseTransition from 'iview/src/components/base/collapse-transition'
import Emitter from 'iview/src/mixins/emitter'
import { findComponentUpward } from 'iview/src/utils/assist'

const prefixCls = 'ivu-tree'

export default {
  name: 'TreeNode',
  mixins: [ Emitter ],
  components: { CollapseTransition, Render },
  props: {
    data: {
      type: Object,
      default () {
        return {}
      }
    },
    multiple: {
      type: Boolean,
      default: false
    },
    childrenKey: {
      type: String,
      default: 'children'
    },
    showCheckbox: {
      type: Boolean,
      default: false
    }
  },
  data () {
    return {
      prefixCls: prefixCls
    }
  },
  computed: {
    classes () {
      return [
        `${prefixCls}-children`
      ]
    },
    selectedCls () {
      return [
        {
          [`${prefixCls}-node-selected`]: this.data.selected
        }
      ]
    },
    arrowClasses () {
      return [
        `${prefixCls}-arrow`,
        {
          [`${prefixCls}-arrow-disabled`]: this.data.disabled,
          [`${prefixCls}-arrow-open`]: this.data.expand
        }
      ]
    },
    titleClasses () {
      return [
        `${prefixCls}-title`,
        {
          [`${prefixCls}-title-selected`]: this.data.selected
        }
      ]
    },
    showArrow () {
      return (this.data[this.childrenKey] && this.data[this.childrenKey].length) || ('loading' in this.data && !this.data.loading)
    },
    showLoading () {
      return 'loading' in this.data && this.data.loading
    },
    isParentRender () {
      const Tree = findComponentUpward(this, 'Tree')
      return Tree && Tree.render
    },
    parentRender () {
      const Tree = findComponentUpward(this, 'Tree')
      if (Tree && Tree.render) {
        return Tree.render
      } else {
        return null
      }
    },
    node () {
      const Tree = findComponentUpward(this, 'Tree')
      if (Tree) {
        // 将所有的 node（即flatState）和当前 node 都传递
        return [Tree.flatState, Tree.flatState.find(item => item.nodeKey === this.data.nodeKey)]
      } else {
        return []
      }
    },
    children () {
      return this.data[this.childrenKey]
    }
  },
  methods: {
    handleExpand () {
      const item = this.data
      if (item.disabled) return

      // async loading
      if (item[this.childrenKey].length === 0) {
        const tree = findComponentUpward(this, 'Tree')
        if (tree && tree.loadData) {
          this.$set(this.data, 'loading', true)
          tree.loadData(item, children => {
            this.$set(this.data, 'loading', false)
            if (children.length) {
              this.$set(this.data, this.childrenKey, children)
              this.$nextTick(() => this.handleExpand())
            }
          })
          return
        }
      }

      if (item[this.childrenKey] && item[this.childrenKey].length) {
        this.$set(this.data, 'expand', !this.data.expand)
        this.dispatch('Tree', 'toggle-expand', this.data)
      }
    },
    handleSelect () {
      if (this.data.disabled) return
      this.dispatch('Tree', 'on-selected', this.data.nodeKey)
    },
    handleCheck () {
      if (this.data.disabled) return
      const changes = {
        checked: !this.data.checked && !this.data.indeterminate,
        nodeKey: this.data.nodeKey
      }
      this.dispatch('Tree', 'on-check', changes)
    }
  }
}
</script>
